Achieving solar-to-hydrogen efficiencies above 15% is important for the commercial success of photoelectrochemical water splitting devices. While tandem cells can reach those efficiencies, increasing the catalytic activity and long-term stability remains a significant challenge. Hydrogen, utilized in fuel cells to power electric motors or burned in internal combustion engines, is an environmentally friendly energy carrier with the potential to reduce our dependence on fossil fuels. However, the production of hydrogen by the traditional gasification of coal and oil and by steam-methane reforming produces large amounts of carbon dioxide, which has implications for climate change. An alternative long-term, sustainable pathway to hydrogen production is a photoelectrochemical (PEC) cell that absorbs sunlight and converts this energy into hydrogen and oxygen via the dissociation of water molecules. Oxide semiconductor materials, such as Fe2O3, WO3, SrTiO3 and TiO2, have been studied for many years for PEC water splitting. However, the slow charge transport kinetics and/or large band gaps that typically define these oxide semiconductors result in very low energy conversion efficiencies. In addition, many materials typically used in PEC cells are susceptible to corrosion during the water splitting process. To realize and commercialize future solar hydrogen concepts based on PEC devices, durability of tens of thousands of hours and a device cost of hundreds of dollars per square meter must be achieved. Thus, it is important to explore possible surface stabilization and catalytic approaches that may improve PEC cell performances, stabilities, and life-spans.